文章来源:未知 文章作者:meng 发布时间:2010-03-01 01:51 字体: [ ]  进入论坛

Two species of damselfish(小热带鱼) may look identical—not to mention drab浅褐色 —to the human eye. But that's because, in comparison to(与……相比) the fish, all of us are essentially1 colorblind(色盲的) . A new study published online on February 25th in Current Biology, a Cell Press publication, reveals that the fish can easily tell one species from another based entirely2 on the shape of the ultraviolet (UV紫外线) patterns on their faces. Although scientists have long known that some animals have UV vision, the new findings suggest that this sense can be keener and perhaps more useful as a "communication channel" than had been anticipated, according to the researchers.

"Researchers have been assuming for a long time that UV vision is not very good—and that it is only useful for detecting the presence and absence of UV light, or objects in front of UV bright backgrounds," said Ulrike Siebeck of the University of Queensland in Australia. "The exciting thing is that we can show that these fish can tell the difference between intricate(复杂的,错综的) UV patterns—something that was not expected based on previous assumptions."

In fact, researchers had some good reasons to doubt the precision of UV vision. The short wavelengths3 of light that characterize UV are prone4 to(易于……) scattering5 in air and water. And even animals that can see in the UV range usually don't have all that many UV cones6(锥形体,视锥细胞) , or photoreceptors, in their eyes. But apparently7 nobody told that to the damselfish.

In the new experiments, Siebeck's team presented the very aggressive fish with two intruders, representing different species that vary in appearance only in their UV patterns. Those initial choice tests showed that the fish always attacked one species over the other. But, when the researchers took away the fishes' ability to see in UV, that preference between species disappeared.

The researchers next transferred the two species-specific UV patterns onto otherwise blank pieces of paper. They trained the fish to swim up to and nudge(轻推,推进) one of the patterns by offering food rewards. When the fish were later presented with both patterns, they still selected the pattern they had been trained on.

Put together, the two lines of evidence support the notion that the UV patterns are both necessary and sufficient for the fish to tell the two species apart.

The ability to see in this visual field is likely quite convenient for the fish, Siebeck said. "If you think about it in simple terms, fish have to be inconspicuous(不显眼的) if they want to go undetected by their predators9(掠夺者,捕食者) and prey10, but at the same time, they have to be conspicuous8 if they want to attract the attention of potential mates, for example. Using UV patterns to do this is a clever way to maximize both at the same time—they are still inconspicuous to predators but very conspicuous to other fish with UV vision."

The researchers say the new findings now call for more detailed11 investigation12 of UV vision in damselfish and other UV-sighted animals, to find out just how well animals can see in this range, and over what distances. The researchers are also testing whether fish can tell different individuals—as opposed to whole species—apart based on fine-scale variation in their UV facial(面部的,表面的) patterns.


1 essentially nntxw     
  • Really great men are essentially modest.真正的伟人大都很谦虚。
  • She is an essentially selfish person.她本质上是个自私自利的人。
2 entirely entirely     
  • The fire was entirely caused by their neglect of duty. 那场火灾完全是由于他们失职而引起的。
  • His life was entirely given up to the educational work. 他的一生统统献给了教育工作。
3 wavelengths 55c7c1db2849f4af018e7824d42c3ff2     
n.波长( wavelength的名词复数 );具有相同的/不同的思路;合拍;不合拍
  • I find him difficult to talk to—we're on completely different wavelengths. 我没法和他谈话,因为我们俩完全不对路。 来自《简明英汉词典》
  • Sunlight consists of different wavelengths of radiation. 阳光由几种不同波长的射线组成。 来自辞典例句
4 prone 50bzu     
  • Some people are prone to jump to hasty conclusions.有些人往往作出轻率的结论。
  • He is prone to lose his temper when people disagree with him.人家一不同意他的意见,他就发脾气。
5 scattering 91b52389e84f945a976e96cd577a4e0c     
  • The child felle into a rage and began scattering its toys about. 这孩子突发狂怒,把玩具扔得满地都是。 来自《简明英汉词典》
  • The farmers are scattering seed. 农夫们在播种。 来自《简明英汉词典》
6 cones 1928ec03844308f65ae62221b11e81e3     
n.(人眼)圆锥细胞;圆锥体( cone的名词复数 );球果;圆锥形东西;(盛冰淇淋的)锥形蛋卷筒
  • In the pines squirrels commonly chew off and drop entire cones. 松树上的松鼠通常咬掉和弄落整个球果。 来自辞典例句
  • Many children would rather eat ice cream from cones than from dishes. 许多小孩喜欢吃蛋卷冰淇淋胜过盘装冰淇淋。 来自辞典例句
7 apparently tMmyQ     
  • An apparently blind alley leads suddenly into an open space.山穷水尽,豁然开朗。
  • He was apparently much surprised at the news.他对那个消息显然感到十分惊异。
8 conspicuous spszE     
  • It is conspicuous that smoking is harmful to health.很明显,抽烟对健康有害。
  • Its colouring makes it highly conspicuous.它的色彩使它非常惹人注目。
9 predators 48b965855934a5395e409c1112d94f63     
n.食肉动物( predator的名词复数 );奴役他人者(尤指在财务或性关系方面)
  • birds and their earthbound predators 鸟和地面上捕食它们的动物
  • The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》
10 prey g1czH     
  • Stronger animals prey on weaker ones.弱肉强食。
  • The lion was hunting for its prey.狮子在寻找猎物。
11 detailed xuNzms     
  • He had made a detailed study of the terrain.他对地形作了缜密的研究。
  • A detailed list of our publications is available on request.我们的出版物有一份详细的目录备索。
12 investigation MRKzq     
  • In an investigation,a new fact became known, which told against him.在调查中新发现了一件对他不利的事实。
  • He drew the conclusion by building on his own investigation.他根据自己的调查研究作出结论。
TAG标签: face human fish UV